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Research on Balance Therapy Goes Virtual
University of Pittsburgh virtual reality grocery store simulates the challenge of shopping for people who have balance disorders. Photo courtesy of the University of Pittsburgh Medical Center.
Adrenaline junkies crave it—the thrill of zooming around curves, up and down hills, and being a tad off balance—and virtual reality games have become an easy way to simulate those sensations. Now an innovative research project is harnessing virtual reality technology, particularly its ability to challenge one’s sense of equilibrium, as a potential therapy for people with balance disorders and chronic dizziness.
With a grant from NIDCD, University of Pittsburgh Medical Center (UPMC) researchers have established a Medical Virtual Reality Center to study how people maintain balance and to identify potential therapies for balance problems. Their studies are advancing the understanding of balance, including components of good balance and factors that lead to poor balance.
The centerpiece of the Medical Virtual Reality Center is a virtual reality grocery store to test a new model for balance rehabilitation. A custom-built treadmill and four computer-controlled projection systems simulate grocery store aisles that range from visually simple (think white paper goods) to daunting (imagine pain relievers, vitamins, and allergy remedies). A person walking on the treadmill controls his or her own speed up the aisle and turns down the next aisle by pushing on one side of a real shopping cart adapted for the facility.
The idea is that individuals with dizziness and balance problems can lessen their symptoms over several weeks by practicing for at least an hour per week at increasingly complex tasks in the virtual grocery store, explains Susan Whitney, Ph.D., associate professor of physical therapy at the University of Pittsburgh School of Health and Rehabilitation Sciences.
Clinical trials are underway, and although results are not in, researchers are optimistic. “It appears that people who are bothered by motion get better,” she says.
Dizziness Impacts Millions
Millions of Americans experience balance and dizziness problems. Good balance relies on three separate senses working harmoniously together: the inner ear, vision, and feedback from muscles and joints on body position. Problems in any one of these systems can result in a balance disorder. There are more than a dozen different diagnosable balance disorders that together affect millions of Americans at some point in their lives, most commonly in older age.
More than a quarter of people between ages 65 and 74 experienced dizziness or difficulty with balance in a 12-month period, according to data from a national public health survey.
People who have balance disorders tend to avoid situations that provoke their symptoms. Certain visual cues combined with motion and head turning can make a person feel unbalanced and dizzy or that they are falling or spinning, explains Dr. Whitney. For some, facing such situations, like a grocery store’s dizzying array of products and crowds of shoppers, can become anxiety-filled experiences.
Therapy in the virtual reality grocery store seeks to address both the physical and emotional aspects of balance disorders in a controlled environment. “What we’re doing here is physical and behavioral therapy. We expose people to gradually more complex scenes,” says Dr. Whitney.
The patients’ ability to control their own speed and discontinue the session if symptoms occur serves to lessen anxiety and fear, Dr. Whitney explains. Then practice at various assigned tasks in the virtual store helps improve their ability to balance and restore confidence. “They seem to get a lot less dizzy,” she says.
Seizing a New Opportunity: Medical Virtual Reality
The idea to use a device like a treadmill for balance rehabilitation first came up in a brainstorming session among Joseph Furman, M.D., Ph.D., director of the Division of Balance Disorders at UPMC, Mark Redfern, Ph.D., professor of bioengineering, and Dr. Whitney a couple of decades ago, she recalls. Dr. Furman asked her what piece of equipment might be most helpful. She replied that patients might benefit from practice on an airport-style moving walkway. Installing such a device was impractical though, until virtual reality came along.
UPMC received NIDCD funding for the Medical Virtual Reality Center in 2001. About a dozen UPMC researchers collaborate on a variety of studies at the center, which accommodates experiments beyond the virtual grocery store. The researchers chose to create a virtual reality grocery store since so many of the people they treat for balance disorders find grocery shopping to be challenging and anxiety-provoking.
Careful attention went into designing the projection system, which casts images of a supermarket floor and product-filled shelves to the front and sides of the treadmill. In addition, the custom treadmill is wider than most to accommodate people who may not be able to walk in a straight line. The treadmill is regularly moved out of the virtual reality space to allow for studies that have participants stand in place.
Art Institute of Pittsburgh students Jacob Galito and Anton Kozlov, working under the direction of Patrick Sparto, Ph.D., associate professor of physical therapy, have helped give the virtual grocery store a realistic appearance. Mr. Kozlov is currently working to add avatars—computer generated shoppers—and obstacles, such as boxes and displays, that one might encounter on an actual shopping trip.
The aisles in the virtual store become progressively more challenging as a person successfully navigates from one to the next. In balance therapy sessions, people try to locate a product beginning with easy tasks such as finding paper towels in the paper goods aisle. They work their way towards more complex, visually challenging tasks such as finding a small, colorful spice jar amid scores of baking ingredients.
The facility is unique in the United States, and Dr. Whitney knows of only one other virtual grocery store for balance rehabilitation in the world—at the University of Haifa in Israel.
To help assess the effectiveness of virtual reality therapy, Dr. Whitney is currently conducting a clinical trial with people who experience dizziness and balance problems. The participants are randomly assigned to one of two groups for six weeks of treatment. One group will work on increasingly difficult tasks in the virtual grocery store for at least one hour per week. The other group will perform traditional balance therapy exercises designed to improve strength, posture, gait, and other components of balance, as well as to avoid falls. To avoid bias in the results, the pre- and post-treatment testing is conducted by a physical therapist who does not know, or is “blinded” to, the type of treatment the participants received.
Earlier research tested the safety of virtual reality balance therapy on healthy volunteers. Dr. Whitney and other UPMC researchers have gathered extensive data on how people respond to the virtual reality grocery store. They have observed people with and without balance disorders standing in or walking in the store’s aisles. They have also studied the responses of various age groups from children to older adults. They have tracked the speed of eye and head movements and distance traveled as people try to locate a product. These measurements help create a picture of the range of responses in people with good and poor balance.
If clinical trials show promising results, Dr. Whitney says, the next step would be to work on developing a plug-and-play version of the virtual reality grocery store for practical use in a physical therapy clinic or at home. Since setting up a costly treadmill and projection system would be beyond the means of clinics, Dr. Whitney envisions a head-mounted visor system, similar to commercial gaming systems, to recreate the virtual grocery store experience.
The device could keep track of an individual’s progress, she says. People using the system at home, under a therapist’s guidance, could also be motivated by higher scores as they improve. “The idea is that if it’s more fun, people work harder. The chance of having compliance and overcoming anxiety is better.”
Visit the University of Pittsburgh Medical Center’s virtual grocery store.